No, none of the normal hallmarks, but the transformer is in an odd spot on the bottom of the game, and there's a surprising amount of fusing for this game. Could all be quite normal for it, but I have never seen another to know - I did reach out to another person that had previously owned one and they didn't recall it being battery operated. There are about 4000 plays on the meter. There's no rectifier, so the conversion was either not complete or never happened. I'm leaning towards the transformer being original.
I'm aware that there was a lot of attrition for manufacturers during each changeover period for pinball -- those that couldn't adapt died.
But this all got me wondering, when was the last battery powered machine released (any manufacturer)? I'm thinking it could have rolled into 1940 fairly easily, but I don't have enough experience/knowledge. I've worked on older and I've worked on newer, but nothing from 1940 itself.